If true, FST errors are fatal. Otherwise, returned objects are flagged as bad.
For example, FSTs are returned with the kError property set to true, and
FST weights set so that Member() returns false. Default: true.

--fst_field_separator=STRING

Set the characters used as a separator between printed fields. Default:
" ".

--fst_read_mode=STRING

Set the default file reading mode for mappable files, either "read" or "map".
Default: "read".

--fst_verify_properties[=BOOLEAN]

Verify fst properties queried by TestProperties. Default: false.

--fst_weight_parentheses=STRING

Set the characters enclosing the first weight of a printed composite weight
(e.g., pair weight, tuple weight, and derived classes) to ensure proper I/O of
nested composite weights. Must have size 0 (none) or 2 (open and close
parenthesis). Default: no parentheses.

--fst_weight_separator=CHARACTER

Set the character separator between printed composite weights. Default: comma.